S-91274A284 5/16"-18 x 3 1/2" ASME B18.3, ASTM A574, ASTM B117 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-flake coating, ideal for harsh industrial environments requiring long-term durability
• Exceptional tensile strength of 170,000 psi ensures reliable performance in high-stress applications and prevents fastener failure
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies in critical machinery
• Hex socket drive design allows for high torque application and easy installation in confined spaces with standard tools
• Partially threaded shank offers optimal grip and clamping force control for precise component positioning
• Compliance with ASME B18.3 and ASTM A574 guarantees consistent quality and interchangeability in professional applications
• RoHS 3 and REACH compliance ensures environmental safety and meets international regulatory standards for industrial use

Professional Applications & Engineering Value

This zinc-flake-coated alloy steel socket head cap screw is engineered to address critical challenges in heavy-duty industrial settings. The 5/16"-18 UNC coarse thread and Class 3A thread fit provide superior resistance to loosening under vibration, making it ideal for machinery, automotive assemblies, and structural frameworks. The high tensile strength and Rockwell C37 hardness ensure durability in high-load applications, while the corrosion-resistant zinc-flake coating extends service life in humid or chemically aggressive environments. Its partially threaded design allows for precise clamping without damaging sensitive components, offering engineers a reliable fastening solution that combines mechanical performance with regulatory compliance.

Specification Summary & Compliance

This socket head cap screw features a 5/16"-18 UNC coarse thread with Class 3A precision fit, ensuring tight tolerances for secure fastening. It meets ASME B18.3 and ASTM A574 manufacturing specifications, guaranteeing dimensional accuracy and material consistency. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for use in environmentally conscious and regulated industries.